Four-Thirds lenses

Left: Zuiko Digital 50-200mm 1:2.8-3.5 Right: Zuiko Digital 40-150mm 1:4-5.6 image by Tim Williams (Image rights)

Owing to the cooperative nature of the Four-Thirds standard, several manufacturers currently produce lenses for it. Whereas a company like Sigma usually produces lenses for another company's cameras without the official blessing of that company — and therefore must design its equipment through reverse-engineering — as it is signed up as a Four-Thirds partner it has access to all the design specifications and technologies as laid out by Olympus in the Four-Thirds white paper. All 4/3rds lenses are fully compatible with other 4/3rds system equipment.

Owing to the size of the Four-Thirds system sensors, the focal lengths of the lenses below should be doubled for their effective focal length equivalents in 24×36mm format.

Olympus Zuiko Digital lenses

All Olympus Zuiko Digital lenses are designed for the 4/3rds image sensor format. Similarly to Canon's EOS system, they have fully electronic mounts with no mechanical connections to the camera bodies at all — a side effect of which is that even manual focus is achieved via an electronic 'focus-by-wire' system. Later Zuiko Digital lenses (late 2007 onwards) featuring Olympus' new Supersonic Wave Drive (SWD) motor are eschewing 'focus-by-wire' in favour of traditional focus ring technology.

Zuiko Digital 25mm 1:2.8 on Olympus E-420 image by Juan Felipe Gómez (Image rights)

Olympus divides its Zuiko Digital range into three tiers of features, build quality and price, each tier broadening out the focal length range, i.e.

• Standard: 14mm to 150mm in eight, F2.8-6.3 lenses.
• High Grade: 11mm to 200mm in seven, F2-4 lenses.
• Super High Grade: 7mm to 250mm in six, generally 'Constant Aperture' lenses.

All lenses are sold with a lens hood, bag and most of the 'High' and 'Super High' grade lenses come with a tripod bracket.

Terminology

• ED — 'Extra-Low Distortion' elements to minimise refraction and reduce chromatic aberrations
• SWD — In Olympus' second generation of lenses, the 'Supersonic Wave Drive' motors promise almost silent, very fast autofocus. Olympus claims that coupled with the E-3 they will provide 'the world's fastest autofocus system in their class'.

Standard lenses

The lenses in this range are 'consumer grade'; they are not weather-sealed, have lower build quality and smaller, non-constant maximum apertures. However, optical quality is considered to better value for money than competitors' products.

• Zuiko Digital 9–18mm F4.0-5.6 ED — Lightweight wide-angle zoom with 62 to 100 degrees field of view (release announced May 13, 2008, available since September 2008)
• Zuiko Digital 14–45mm F3.5–5.6 — The original standard 'kit' lens with all consumer Olympus cameras from the E-300 onwards. Now discontinued.
• Zuiko Digital ED 14–42mm F3.5–5.6 ED — New, smaller and lighter standard 'kit' lens for E-410, etc. Has a blue ring around the front element, and a plastic mount.
• Zuiko Digital 17.5–45mm F3.5–5.6 —A 'Special Edition' lens that was released with the E-500 in a SE kit. Now discontinued.
• Zuiko Digital 40–150mm F3.5–4.5 — The original telephoto lens in Olympus 2-lens kits. Now discontinued.
• Zuiko Digital ED 40–150mm F4–5.6 ED — New, smaller and lighter telephoto kit lens for E-410 & E-510. Slower maximum aperture at all focal lengths the the preceding 40-150mm and a plastic lens mount, though much smaller and lighter than its predecessor.
• Zuiko Digital ED 18–180mm F3.5–6.3 ED — A 10x 'zoom' thought to be a re-badged and/or re-engineered Sigma 18-200 F3.5–6.3 DC.
• Zuiko Digital ED 70–300mm F4–5.6 ED — Thought to be a re-badged/re-engineered Sigma, as the optical elements are identical to Sigma 70-300mm f/4-5.6 APO DG Macro.
• Zuiko Digital ED 25mm F2.8 pancake — Compact prime, weighing 95g and 23mm deep.
• Zuiko Digital 35mm F3.5 Macro — Maximum magnification of 1.0x, very small and light.

High grade lenses

Zuiko Digital 12-60mm 1:2.8-4 image by Tim Williams (Image rights)

Of better construction than their ‘Standard’ tier counterparts, they add dust and moisture-sealing, have a ‘Focus Distance Scale’ window on the lens body and have internal focusing. All the ‘zoom’ lenses in this tier are varifocal and have a variable maximum aperture as the focal length increases. The zoom factor of these lenses is generally in the 3 to 4x range, the exception among the zoom lenses being the ‘2×’ 11–22.

• Zuiko Digital ED 8mm F3.5 ED Fisheye — Produces a full frame, non-circular image.
• Zuiko Digital 11–22mm F2.8–3.5 ED
• Zuiko Digital 12–60mm F2.8–4 ED SWD — The new ‘kit’ lens with the E-3, the first lens released to feature the new SWD focusing technology.
• Zuiko Digital 14–54mm F2.8–3.5 ED — Released as a ‘kit’ lens for the E-1; available as kit lens for the E-3.
• Zuiko Digital 14–54mm II F2.8–3.5 ED — Released as a ‘kit’ lens for the E-30; same as above with contrast autofocusing.
• Zuiko Digital ED 50mm F2 ED Macro — Maximum magnification of 0.52× — equivalent to 1:1 on 35mm film
• Zuiko Digital ED 50–200mm F2.8–3.5 ED — Supplied with a tripod bracket. Now discontinued.
• Zuiko Digital ED 50–200mm F2.8–3.5 ED SWD — Supplied with a tripod bracket. The SWD model replaced the otherwise optically identical non-SWD version (above).
• Zuiko Digital 'Telephoto Macro' — This lens, thought to be around 100mm, is planned for release in 2008.

Super high grade lenses

Of increased construction standard and better optical quality over their 'High Grade' counterparts, these lenses incorporate all that the lower tiers offer while adding 'Focus Limiter' switches and 'Focus Stop' buttons around the foremost focussing ring. With the exception of the 7-14mm and 14-35mm they all come with a removable tripod bracket. All the lenses in this tier are of a constant aperture and all except the 7-14 have internal focus and internal zoom, which is restricted to 2x or 3x times magnification. On the newer lenses (14-35, 35-100 & 90-250), the lens hoods are lined with a velvet-like material to reduce reflections while incorporating openings for circular polariser use.

• Zuiko Digital ED 7–14mm F4 ED— Fixed lens hood with no filter thread.
• Zuiko Digital ED 14–35mm F2 ED SWD — This lens features the new SWD focusing technology, therefore foregoing 'Focus By Wire'.
• Zuiko Digital ED 35/100mm F2 ED
• Zuiko Digital ED 90–250mm F2.8 ED
• Zuiko Digital ED 150mm F2 ED
• Zuiko Digital ED 300mm F2.8 ED — Has an opening near the mount to accept filters.

Zuiko Digital 11-22mm 1:2.8-3.5 and Sigma 24mm 1:1.8 EX DG image by Michael Gatchell (Image rights)

Sigma Four-Thirds lenses

The majority of Sigma lenses released for the 4/3rds system are simply adaptations of lenses Sigma previously released for APS-C or 35mm formats.

Terminology

• DC — Lenses marked with this code are designed for digital sensors, and therefore do not have an image circle large enough to suit the full-frame bodies of the system they are mounted for (not a problem for a 4/3rds CCD).
• DG — Lenses with imaging circles large enough to fit 35mm sensors/film (again, not a problem for a 4/3rds CCD).
• EX — Lenses with a better external finish, reportedly to reflect the superior build and optical quality.
• HSM — 'Hyper-Sonic Motor'; this is effectively Sigma's 2nd generation of quieter, faster autofocus motors (and is also in some Olympus 4/3rds lenses)
• ASP — Lenses with one or more aspherical elements, to minimise distortion and allow smaller, lighter designs.
• APO — Lenses with low-dispersion glass to minimise chromatic aberration.

Wide zoom

• Sigma 10-20mm F4-5.6 EX DC HSM

Standard zoom

• Sigma 18–50mm F2.8 EX DC Macro
• Sigma 18–50mm F3.5–5.6 DC — Now discontinued.
• Sigma 18–125mm F3.5–5.6 DC — Now discontinued.

Sigma 30mm 1:1.4 EX DC HSM image by Tim Williams (Image rights)

Telephoto zoom

• Sigma APO 50–500mm F4–6.3 EX DG HSM — Now discontinued.
• Sigma 55–200mm F4–5.6 DC — Now discontinued.
• Sigma APO 70-200mm F2.8 II EX DG Macro HSM
• Sigma APO 135–400mm F4.5–5.6 DG — Now discontinued.
• Sigma APO 300–800mm F5.6 EX DG HSM — Now discontinued.

Macro

• Sigma 105mm F2.8 EX DG Macro
• Sigma APO 150mm F2.8 EX DG HSM Macro

Single focal length

• Sigma 24mm F1.8 EX DG ASP Macro — Now discontinued.
• Sigma 30mm F1.4 EX DC HSM
• Sigma 50mm F1.4 EX DG HSM

Panasonic Four-Thirds lenses

A relative newcomer to the DSLR market, Panasonic (Matsushita) has released two camera bodies — the DMC-L1 and the DMC-L10 — and four lenses for the 4/3rds system. Its lenses are co-branded with Leica, something it began with its Lumix compact digital cameras — it is understood that these lenses are Leica-designed and Matsushita-built.

Panasonic's lenses are unique among those made expressly for the 4/3rds system in having an aperture ring. When used on a Panasonic or Leica body, the aperture can be adjusted with this ring rather than the camera's buttons or dials.

Zoom

• Leica D Vario-Elmarit 1:2-8-3.5/14-50 asph. Mega OIS — Fast Four Thirds kit zoom lens made under license from Leica by Matsushita and sold as a kit with the Leica Digilux 3 and the Panasonic Lumix DMC-L1 camera. It sports Panasonic's lens-based image stabilisation (Panasonic used this optical stabilization system also in its Lumix series of compact digital cameras).
• Leica D Vario-Elmar 1:3.8-5.6/14-50 asph. Mega OIS — Optically stabilized kit lens for the Panasonic DMC-L10. As of June 2008 the only Leica D lens lacking an aperture ring (aperture controlled from camera body).
• Leica D Vario-Elmar 1:3.5-5.6/14-150 asph. Mega OIS — Superzoom (10.7x), first Leica D lens with Extra Silent (XS) Technology.

Single focal length

• 25mm F1.4 Leica D Summilux ASPH.

Conversions to the Four-Thirds mount

The distance between film plane and lens flange of the Four-Thirds system is unusually small, two millimetres less than that of the Konica AR system. This allows enterprising people to adapt older SLR lenses for these cameras.

Without dedicated lens adapter

• Lenses with the Konica AR mount can be adapted. The process is destructive — the lens will no longer be usable with a Konica body — but the only parts needed are spacer rings.
• Recently non-destructive, full reversible and easy adaptation method was published for some of the Hexanon AR lens range.
• Lenses with the Canon FD mount can also be adapted. This similarly renders the lens unusable with a Canon body. It is more complex than conversion of a Konica AR–mount lens, and it also requires the mount of an AR-mount lens.

With dedicated lens adapter

Aftermarket adapters allow non-destructive coupling between Four-Thirds bodies and older manual-focus lenses. A properly tuned adapter will report actual aperture setting and focal length of the lens to the camera (the latter preset parameter enables proper image stabilisation fuctioning).

• Pentax K, Nikon F, Olympus OM, Leica R, Praktica, Contax/Yashica lenses may be attached and will focus manually to infinity.
• Canon FD mount and Minolta MC / MD lenses may be attached, but due to shorter distance between lens flange and film plance will not focus to infinity. Thus their functionality is limited to macro photography.

As an example, "Fotodiox" adapters are made for Minolta MD, Nikon F, Olympus OM, Leica R, M42, Contax/Yashica, and Pentax K mounts.

References

• "Official Four-Thirds Lens Lineup" at Four Thirds.org